Casing for voice synthesizer



FIG. 1 is a top plan view of a casing for a voice synthesizer showing my new design;

FIG. 2 is a front elevational view;

FIG. 3 is a bottom plan view;

FIG. 4 is a side elevational view; and

FIG. 5 is a front, top and left side perspective view. 

The ornamental design for a casing for voice synthesizer, as shown and described. 